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Vakhtangadze et al. Myocardial ischemia in women

EVALUATION AND DIAGNOSIS But how about the detection of microvascular disease?
Angiography cannot record it. Is there a standard
The high incidence of cardiovascular death in for diagnosing microvascular disease? To answer
women, particularly due to CAD, raises the need for these questions, the physiology of tests should be
the early evaluation of women at increased risk in considered. The major advantage of the exercise
order to determine the optimal therapeutic strategies. ECG is that it is inexpensive, and therefore readily and
Coronary angiography remains the reference standard widely available. However, quantification of the extent
for diagnosing ischemic heart disease. However, it of microvascular dysfunction is not possible.
has very low possibilities to evaluating patients with
microvascular angina. Because the majority of patients Direct visualization of the blood supply and hence
with microvascular dysfunction are women, it is very ischemia is possible only by studying perfusion via the
important to determine which tests are of value for well-established tool SPECT and the emerging tool MRI.
their evaluation. Coronary angiography cannot provide
information about the severity and extent of ischemia. The advantages of SPECT stress perfusion images
Thus, in women, non-invasive tests that save money include direct visualization of ischemia, high
and reduce periprocedural risks, are of particular value. interobserver agreement, low operator dependence,
a high technical success rate, high sensitivity, better
The simplest formula - ischemia is mismatch between accuracy when multiple resting left ventricular
oxygen demand and delivery - indicates the importance motion abnormalities are present, and the ability to
of the direct visualization of ischemia in women, detect ischemia in an infarct area. Higher specificity,
particularly because the rate of microvascular angina and greater availability, versatility, and (arguably)
is higher in women than in men. Exercise stress convenience favor the use of stress echocardiography
testing remains the basis for the evaluation and risk- over SPECT. [33-35] However, the lower specificity of
stratification of patients with suspected CAD. It is a SPECT compared to stress-echocardiography may
valuable and informative tool in both men and women. correspond to the presence of microvascular disease,
However, the accuracy of interpreting the test depends which does not currently have clear diagnostic criteria.
not only on ST-segment changes, but also on the Data regarding the use of MRI in this context remain
double product, heart-rate recovery time, and so on. To limited and insufficient. However, it is seems promising.
accurately interpret the results of the test, the pretest
probability of the patient having ischemic heart disease Quantitative rest/stress myocardial perfusion imaging
and her hormonal state should be considered. It is well [best documented using positron emission tomography
known that during the physical exercise test (treadmill (PET)] combined with clinical circumstances usually
or veloergometer), increased oxygen demand and provides a definitive direct visualization of ischemia,
energy consumption lead to ECG changes. [28-32] and is therefore a highly informative tool in the diagnosis
of patients and guiding management, including risk-
It is also well known that an exercise stress test has factor management and revascularization for patients
relatively lower sensitivity and specificity for diagnosing with physiologically severe epicardial stenosis by
ischemia. Meta-analyses have indicated that there quantitative PET. [36]
are frequent false-positive and false-negative results,
and that this test is more valuable in young patients Compared with negative tests, a positive result on
compared with older ones. [29,30] This view has been computed tomography angiography (CTA) in women
echoed in other meta-analysis. [32,33] An analysis of ECG has been found to be more predictive of subsequent
results acquired during exercise stress tests found clinical events than a positive stress test (adjusted P =
sensitivity and specificity of 64% and 81%, respectively, 0.028). [32] Among men, a positive CTA was slightly but
in men, compared with 61% and 65%, respectively, not significantly less informative of risk detection than
in women -- quite a big difference in specificity a positive stress test (adjusted P = 0.168). [28,37,38]
between men and women. Analyses for other imaging
modalities have found sensitivities and specificities, However, all of these results, and all of the sensitivity
respectively, of: 77% and 81% for men compared with and specificity data, refer to the evaluation of patients
78% and 86% for women for stress echocardiography; with obstructive CAD. There are very few data on the
88% and 74% for men compared with 82% and 81% value of these tests in diagnosing microvascular angina,
for women for SPECT; and 86% and 82% for men and this represents a main limitation of current research.
compared with 78% and 74% for women for magnetic
resonance imaging (MRI). [33] In all of these studies, the Evaluating women with chest pain seems to be difficult,
standard for diagnosis (and comparison) was coronary with various pathophysiologic mechanisms behind the
angiography and the presence of obstructive CAD. condition, diverse clinical presentations, and limited
46 Vessel Plus ¦ Volume 1 ¦ June 27, 2017